The fts(3) functions can be tricked by a rogue user into performing
actions on incorrect file system hierarchies.

Technical Details
=================

The macro for chdir used in libc/gen/fts (__fts13.c after NetBSD 1.3)
did not perform sufficient safety checks. If any directory (or symlink
to a directory) above the current directory fts was processing was
moved, the fts-using application could be made to descend the wrong
directory sub-tree, and/or ascend above the original starting directory.
Once it has ascended above the starting directory, the process could
descend into an unintended file system hierarchy.

This is particularly dangerous when combined with automated scripts
which run programs such as 'rm -r'.

Solutions and Workarounds
=========================

The following instructions describe how to upgrade your C library
and affected statically linked system binaries by updating your source
tree and rebuilding and installing a new version of the C library
and affected binaries.

* NetBSD-current:

Systems running NetBSD-current dated from before 2001-06-09
should be upgraded to NetBSD-current dated 2001-06-10 or later.

The following directory needs to be updated from the
netbsd-current CVS branch (aka HEAD):
src/lib/libc